DE2608108A1 - FUEL INJECTION SYSTEM - Google Patents

Description

PLESSEY HANDEL UND INVESTMENTS AG
Gartenstrasse 2
6300 Zug / Switzerland

Our reference: P 2295

Fuel injection system

Addition to the main patent (patent application

P 23 OiJ 525.2)

The invention relates to a further development of the one given in the main patent (patent application P 23 04 525.2)

technical teaching. In particular, the invention relates to a fuel injection system that includes an improved fluid retention valve has, with which fuel is prevented from flowing through a fuel injector to the Times are injected when the nozzle is not vibrated.

The main patent (patent application P 23 OH 525.2) relates to a fuel injection system in which a liquid retention valve, preferably a ball check valve, is arranged in such a way that it normally shuts off and opens the nozzle cross-section of a fuel injection nozzle

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this way prevents the injection of fuel at the times when the nozzle is not being driven by a vibrator is set in vibration.

It has now been found that a fuel injector assembly is advantageous when the valve is within a housing is arranged which is provided in the nozzle. If with such a structure a floating, d. H. freely movable valve, this valve may have the tendency to be on a wall of the Housing, usually the wall opposite the nozzle cross-section, to remain during the times in which the nozzle is made to vibrate. If the vibrations of the nozzle are interrupted, this valve can remain on the wall and it is sometimes difficult to get the valve into place quickly moved back at the nozzle opening, whereby this valve blocks the injection of fuel from the nozzle. It is believed that this is caused by the fuel within the housing which is effective to to press the valve against the wall and / or by pressurized air from a motor which is fed into the nozzle through the Reached nozzle opening and acts on the valve. It is an object of the invention to provide such hang-up to prevent the valve.

The invention creates a fuel injection system, which has a fuel injector nozzle having a fuel injection port, further comprising tin Vibration generator is provided with which the fuel injected from the nozzle is atomized, the Nozzle on the inlet side of the nozzle opening has a liquid retention valve which is arranged and is designed that it is normally the nozzle opening

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blocked and in this way prevents fuel from being injected through the nozzle, and which is so formed is that it moves away from the nozzle opening when the vibrator is turned on, whereby the injection of fuel through the nozzle is enabled, the valve being arranged in a housing in the nozzle and this housing has biasing devices with which the valve is biased towards the nozzle opening when the nozzle is not vibrating.

Preferably the valve is a ball valve, although other shapes of valve formed so can be used are that there is an appropriately sized seat on which the valve can sit.

Preferably the biasing means comprise biasing springs. For example, a helical spring can be arranged in a corresponding manner in the housing in order to act on the valve. The spring can be held in place in the housing by various means, for example in that the spring sits in a recess in the housing, or that the spring is soldered to the housing. The preload spring can also be a leaf spring.

The housing preferably has channels which allow the fuel to be introduced into the housing in such a way that that the fuel is swirled or swirled in the housing.

The vibration generator can have a piezoelectric component. If desired, the valve can be opened by the vibrations take place in such a way that this opening is supported by a magnetic effect on the valve,

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for example with the aid of a solenoid coil, which is energized during the desired injection times, around the nozzle to vibrate. In this case the valve can be made entirely or partially of a magnetic material exist and can be arranged so that it is in one direction from its seat by the magnetic action the energized solenoid coil is pushed away.

In order to further facilitate optimal atomization of the fuel leaving the nozzle, the downstream End portion of the nozzle be equipped with an inwardly projecting annular shoulder, the one sharp-edged opening limited.

The fuel injection system according to the invention can be a Have fuel feed device, by means of which a stream of fuel is supplied to the nozzle. The system can also have a timing that controls the Activation of the nozzle vibrations is limited. For example, ultrasonic vibrations can occur at the same time Periods of time arranged at a distance from one another are limited. Each switching period can have an adjustable part of a cycle, based on the revolutions of an internal combustion engine. The fuel injection system can be used be to fuel directly or usually in the intake line of a two-stroke or four-stroke internal combustion engine injected or in a central heating boiler or in a gas turbine.

When the fuel injector is vibrated, these vibrations are usually ultrasonic vibrations or these vibrations take place with so-called ultrasonic frequencies. These vibrations are evident sufficient so that the fuel is in small mist

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like particles is divided. The candidate frequency range can practically have a lower limit, which is the manschlichen ear near the top Hörbärkeitsgrenze. In order to eliminate noise nuisance, however, it is generally preferred to use frequencies in practice which are high enough to ensure that audible sound is not generated.

Embodiments of the invention will now be described with reference to the figures of the drawing. Show it

1 shows a schematic axial sectional view of an embodiment of a fuel according to the invention injection system,

FIG. 2 shows a detailed sectional view through a nozzle tip which is designed similarly to the nozzle tip in FIG. 1,

Figure 3 is a detailed sectional view of a first modified one Nozzle tip,

Fig. Ι is a sectional view taken along the line X-X in Fig. 3,

Fig. 5 is a detailed sectional view through a second alternative nozzle design

and
FIG. 6 is a sectional view taken along line XX in FIG. 5.

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Reference is now made to FIG. 1. In Pig. I is a line 1 is shown, which is an intake line of an internal combustion engine or, for example, a line, those from the air compressor to the burners of a turbojet engine leads or another gas turbine. To be liquid. Inject fuel into the combustion air, which is assumed to flow through line 1 in the direction of arrow A is a cylindrical nozzle section 2 of a fuel injection nozzle or an atomizer 3 arranged and designed in such a way that this section extends with its end 2a through an opening in the wall of the line 1. The fuel injector extends such that essentially a seal is achieved, but with one Movement in the longitudinal direction of the section 2 is made possible.

The cylindrical portion 2 forms a so-called horn on one side of a portion 5 of a large diameter Resonance vibration amplifier. On the opposite surface of section 5 is a vibration generator attached in the form of a piezoelectric transducer element 6, a calibration body 7 is on the opposite side of the transducer 6 as shown.

The design is such that when an alternating voltage with a given ultrasonic frequency the piezoelectric Component 6 is supplied via wires.9 and 10, the ultrasonic resonance vibrations in the longitudinal direction of the cylindrical horn section 2 are fed to the large diameter section 5 of the vibration amplifier. The amplitude of the vibrations is amplified in the horn section 2, which is dimensioned so that the maximum vibration amplitudes near the outer end 2a of the hornesj

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which extends into the line 1 are generated.

A fuel channel 11 is provided coaxially in the cylindrical grain section 2. In order to form a spray nozzle, this channel is equipped with a limited flow cross-section in the vicinity of the end 2a of the horn section 2 or has an inwardly extending shoulder section 12 which delimits a nozzle opening 13. The section 12 has a conical valve seat surface I ¹ I which cooperates with a ball valve 15. The valve 15 can lift off its valve seat Ik against the pressure of a spring 20.

Liquid fuel under a suitable pressure is fed to channel 11 through a transverse bore 16A, which is formed in section 5 of the vibration amplifier body.

It can be seen that a housing 17 surrounds the ball valve and that fuel from the channel 11 into the interior this housing can enter, mainly through radial slots 16, which can be seen more clearly in FIG are.

Reference is now made to FIGS. 1 and 2. The slots or channels 16 are with the inside of the housing 17 in connection and are preferably arranged, for example tangentially, that the fuel that is in the Interior of the housing 17 is introduced, is swirled. This swirling of the fuel can cause atomization support of the fuel.

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The fuel injection system described so far works in the following manner, usually the fuel in channel 11 and within housing 17 causes the ball valve 15 rests against its valve seat 14. this normally prevents fuel from exiting the fuel injector through orifice 13 and onto it Way is injected into the stream of combustion air in line 1. However, if an alternating voltage with suitable ultrasonic frequency is fed to the piezoelectric transducer 6 via the lines 9 and 10, generate the resulting resonance vibrations of the end portion 2a of the cylindrical horn 2 dynamic forces that act on the Ball valve 15 act. The valve 15 is lifted from its seat 14, and it is possible that fuel is inside of the housing 17 can enter the line 1 through the nozzle opening 13. In this way, channel 1 generated during the occurrence of the ultrasonic vibrations a spray of atomized fuel that intimately is mixed with the combustion air in line 1. In this way, a desired fuel-air mixture is obtained generated as long as voltage with ultrasonic frequency is supplied to the piezoelectric transducer 6.

While the injection nozzle is vibrated, the ball valve 15 moves to the rear 19 of the rear wall of the housing 17. This movement takes place against the pressure exerted by the spring 20 which biases the ball valve 15 against the valve seat 14, as shown in FIG. 1 and 2 show. As soon as the supply of the voltage with ultrasonic frequencies is interrupted, the spring 20 presses the valve 15 against the valve seat 14. Once the valve 15 is on its seat 14, the fuel injection via the nozzle 3 is interrupted, and the pressure of the fuel in the channel 11 and in the housing 17 causes the valve 15 on his

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Seat remains. The spring 20 ensures that the valve 15 moves relatively quickly towards the valve seat Ik when the vibrations are interrupted and this ensures a prompt shut-off of the fuel flow.

In the in-Fig. 1 are the exemplary embodiment shown still other devices are available with which the ball valve 15 can be lifted from its seat I ^ in the times in which injection is desired. These other bodies do not work with a dynamic one Exposure to the ultrasonic vibrations of the nozzle 3.Although these devices can be used independently, they are used in the illustrated embodiment to reduce the flow rate through the ball valve 15 is made possible to rise above that which is achieved when only the inertia effect due to the Vibrations is exploited. These additional devices have a solenoid winding 18 which is around the cylindrical horn section 2 is arranged at a suitable axial location. The cylindrical horn section 2 consists of a non-magnetic material, while the valve 15 is made of a magnetized steel or a other suitable magnetic material. The winding is arranged so that the valve 15 from its seat 14 is lifted off by magnetic action when the solenoid winding 18 is energized.

The excitation current is preferably a direct current, otherwise the cylindrical section 2 is made of one material would have to be, which has a correspondingly low electrical conductivity, in order to have an undesirable shielding effect to be switched off by induced currents.

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Suitable devices can be provided which carry out a suitable timing of the excitation current pulses for the winding 18. In the illustrated embodiment, the pulses are controlled in such a way that they coincide with the pulses of the ultrasonic frequency current which is fed to the piezoelectric component 16, in that a rectifier 22 »2Ά is connected in parallel to the lines 9 and 10, as indicated by dash-dotted lines the connecting lines 9a, 10a is indicated.

Reference is now made to FIGS. 3 and 4. These show a first alternative embodiment of the nozzle tip. The housing 17 is also present, however the surface 19 of the rear wall is curved. The spring 20 rests against the curved surface 19.

Figures 3 and H show four channels 16 which are arranged to enter the housing 17 tangentially to cause good fuel swirl in the housing. The fuel in the channel 11 reaches the channels 16 by flowing through the annular space 23 between the outside of the housing 17 and the wall of the channel 11.

Reference is now made to FIGS. 5 and G. These show a second alternative embodiment of the nozzle tip. This embodiment is similar to that shown in Figures 3 and H , and it can be seen that the surface 19 of the rear wall of the housing 17 is curved. The spring 20 is supported against this curved surface 19.

In Figs. 5 and 6 four channels 16 are shown, the so are arranged so that they open tangentially into the housing 17 in order to have a good fuel swirl in the

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Cause housing. The outside of the housing 17 is, for example, by soldering over the entire Length at the four points 27 connected to the inside of the cylindrical nozzle section 2. How clear Fig. 6 shows, four spaces 29 are then left free, which between the inside of the nozzle section 2 and the Outside of the · housing 17 are formed, and fuel can flow through the channel 11 and then through the spaces 29 into the channels 16. With an alternative Alteration, the housing 17 can initially cover the inner surface of the nozzle section 2 substantially touch the entire circumference and then longitudinal channels can be drilled to allow fuel from the channel 11 can flow to channels 16.

It should be noted that in the embodiment shown in FIGS. 5 and 6, the housing 17 is so fixed to the nozzle portion 2 is connected that the housing 17 and the nozzle section 2 are viewed as a one-piece full component can be. This can bring advantages in the case of ultrasonic vibrations, because the housing 17 then no longer has a tendency to oscillate relative to the nozzle section 2 or to move relative to this section and better atomization of the fuel can be achieved because the ball valve 15 responds more quickly to the stop and the triggering of the vibrations responds.

In addition to securing the housing 17 along its length At the nozzle section 2 there are various other factors that can affect the atomization of the fuel from the nozzle section 2 can influence. First, the amount of atomized fuel can be increased when the nozzle portion 2 is vibrated over an increasing period of time.

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Second, the amount of atomized fuel through the nozzle 2 can be increased if the number of vibrations per constant period of time.

Third, the size and mass of the ball valve 15 can die affect the fuel atomization achieved.

Fourth, the number and arrangement of the channels 16 and the size of the housing 17 affect the fuel atomization achieved.

Fifth, the internal shape of the housing 17 can be used to affect fuel atomization. For example, in FIGS. 1 to 6, the part of the housing 17 next to the opening 13 is conical towards the opening educated. As a result, consumption gases that flow from the line 1 through the opening 13 can be increased Pressure act on the ball valve 15 in order to release it from the opening 13 against the action of the spring to push away.

The above embodiments have been given to illustrate the invention, and modifications can be made which are within the scope of the invention. For example, the solenoid training can be in different Way are changed, such that a non-magnetic valve is connected to a magnetic armature so that both can move together. ~

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Claims (6)

Claims 1. A fuel injection system with a fuel injector nozzle; which has an injection port, and with a vibration generator through which the fuel flows through the nozzle is injected, is atomized, the nozzle at the inlet side of the nozzle opening with a liquid retention valve is equipped, which is designed so that normally the nozzle opening is closed and the injection of fuel through the nozzle is prevented and wherein the formation is further such that this valve can move away from the nozzle opening when the vibrator is switched on, whereby the Injection of fuel through the nozzle is allowed, according to the main patent (patent application P 23 O ^ 525.2), characterized in that the valve (15) is arranged in a housing (17) in the nozzle and that this housing a biasing device (20) with which the valve is biased towards the nozzle opening when the nozzle is not vibrating. 2. Fuel injection system according to claim 1, characterized in that that the valve is a ball valve. 3 · Fuel injection system according to claim 1 or 2, characterized characterized in that the biasing means is a biasing spring. ^ 4. Fuel injection system according to claim 3 »characterized in that that the bias spring is a coil spring. 609838/0251 5. Fuel injection system according to one of claims 1 to 4, characterized in that the housing has channels, which allow fuel to be introduced into the housing in such a way that the fuel in the housing has a Performs whirling motion. 6. Fuel injection system according to one of claims 1 to 5, characterized in that the vibration generator comprises a piezoelectric component. 609838/0261 4S Blank page